Robert W. (Bob) Mattson, Jr. (born May 31, 1948) is an American lawyer who held elective political office in Minnesota, and is also involved in various business ventures in Florida, Colorado and Canada. He served one term as Minnesota State Auditor from 1975–1979, and was Minnesota State Treasurer from 1983–1987. He is a member of the Democratic–Farmer–Labor Party. His father was Minnesota Attorney General Robert W.